Detached Eddy Simulations of a Simplified Tractor/Trailer Geometry

Sie sind hier: Homepage > Suche

Detached Eddy Simulations of a Simplified Tractor/Trailer Geometry

Roy, Christopher J. / Ghuge, Harshavardhan A.

Detached Eddy Simulations (DES) are presented for the flow over simplified tractor/trailer geometry at zero degrees yaw angle. The simulations are conducted using a multi-block, structured computational fluid dynamics code. Coarse and fine grids of 3.8 million and 13.2 million cells, respectively, are used for the simulations. The analysis involves estimation of the period of initial flow transients as well as the period required to obtain statistical convergence, and suggests that prior DES studies for this case were not run long enough to ensure statistical independence. Time-averaged quantities compared with experimental data include vehicle drag, surface pressure and wake velocities. The drag coefficient predicted by the DES model matches closely with the experimental value; however, the DES model fails to accurately capture the details of the turbulent flow in the near wake of the trailer base. The simulations on the fine grid show significant improvement over the coarse grid results. Fourier analysis of the unsteady pressures in the base region suggests that the discrepancies in the near wake are/may be due to the improper transfer of turbulence information from the attached boundary layers (which are modeled with the Spalart-Allmaras RANS model) to the turbulent wake where LES-type modeling is used.